This was put together by Dr M. Khurram Wadee of the University of Exeter, who writes:

You might be interested in knowing that your free art was processed by me with free software, namely: GNU/Linux, GNU/Emacs to produce a monthly calendar in LaTeX format and your PNG files were processed using Netpbm programs. Almost all of my technical work is done using free software and I don’t know where I’d be without it.